8198( 4) - 02/29/00 11:19 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8198 Version: 4 Check-in Date: 29-Feb-2000 11:18:24 1.Proposal Title: Understanding the Starburst-like Dust in the Small Magellanic Cloud ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Karl Gordon University of Arizona CoI: Dr. Geoffrey Clayton Louisiana State University N CoI: Dr. Michael Wolff Space Science Institute N ------------------------------------------------------------------------------------ 5. Abstract The similarities between the ultraviolet extinction found in the star forming bar of the Small Magellanic Cloud (SMC) and starburst galaxies has highlighted the importance of understanding the dust extinction in the SMC. The behavior of the UV extinction in the SMC is unlike that seen in any other Local Group galaxy. In a recent study, it was shown that the traditional (no 2175 Angstrom\ bump, high far-UV rise) SMC extinction curve is seen in the SMC's star forming bar, while outside of this bar a much more Galactic (2175 Angstrom\ bump, weaker far-UV rise) extinction curve is seen. These results are tentative due to the fact that only four extinction curves are known with certainty in the entire SMC. We propose to determine the ultraviolet extinction curves toward three additional stars stars in the SMC. These sightlines were chosen to be located near differing levels of star formation activity. In addition to helping understand the origin of the UV dust extinction in st arburst galaxies, study of the spatial variation of UV extinction in the SMC also holds the promise of helping to understand the origin of the 2175 Angstrom\ bump. Understanding the behavior of dust in starburst regions is important as the differences between the extinction corrections for the Milky Way and the SMC is a factor of 10 at 1500 Angstrom. ------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 2] Observations Description ------------------------ Our target signal-to-noise ratio (S/N) is 50 per resolution element which will allow us to use the star's spectral features to determine it's UV spectral type. For AzV 4, the exposure time to get a S/N of 50 using STIS/FUV with G140L is 270 seconds. The corresponding exposure time for the STIS/NUV with G230L is 425 seconds. Combining both exposures, guide star acquisition, STIS acquisition, and 2 readouts of the MAMAs gives a total of 36 minutes. For the declination of the SMC, the visibility period is 58 minutes. Thus, we can get a UV spectrum of AzV 4 in under a one orbit. The calculations for the other stars are similar. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 AZV4 EXT-STAR, B0-B2 III-I RA=0H 45M 3.4S +/- 0.4", DEC=- J2000 F(1500)=6+/-1e-14 72D 41' 57.1" +/- 0.4", PLATE- F(2000)=4+/-1e-14 ID=0024 V = 13.86+/-0.05 B-V = +0.09+/-0.02 2 AZV218 EXT-STAR, B0-B2 III-I RA=00H 59M 04.0S +/- 1.0", DEC=- J2000 F(1500)=1+/-0.2e-13 72D 19' 40.0" +/- 1.0", PLATE- F(2000)=8+/-0.5e-14 ID=06B1 V = 13.80+/-0.05 B-V = -0.13+/-0.02 3 AZV132 EXT-STAR, B0-B2 III-I RA=00H 52M 41.6S +/- 0.3", DEC=- J2000 F(1500)=2+/-0.5e-14 73D 12' 9.3" +/- 0.3", PLATE- F(2000)=3+/-0.5e-14 ID=06B1 V = 13.63+/-0.05 B-V = +0.09+/-0.02 4 AZV86 EXT-STAR, B0-B2 III-I RA=00H 51M 5.8S +/- 0.3", DEC=- J2000 F(1500)=6+/-0.5e-13 72D 0' 30.4" +/- 0.3", PLATE- F(2000)=3+/-0.5e-13 ID=06B1 V = 12.83+/-0.05 B-V = -0.16+/-0.02 5 AZV23 EXT-STAR, B0-B2 III-I RA=00H 47M 38.9S +/- 0.3", DEC=- J2000 F(1500)=3+/-0.5e-14 73D 22' 53.6" +/- 0.3", PLATE- F(2000)=6+/-0.5e-14 ID=06B1 V = 12.25+/-0.05 B-V = +0.07+/-0.02 6 AZV404 EXT-STAR, B0-B2 III-I RA=01H 6M 29.3S +/- 0.3", DEC=- J2000 F(1500)=6+/-0.2e-13 72D 22' 8.5" +/- 0.3", PLATE- F(2000)=3+/-0.2e-13 ID=06B1 V = 12.20+/-0.05 B-V = -0.12+/-0.02 8198( 4) - 02/29/00 11:19 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 5 AZV4 STIS/C ACQ F28X50L MIRROR 1 0.2 S ONBOARD ACQ FOR 10 CD P ------------------------------------------------------------------------------------------------------------------------------------ 10 AZV4 STIS/N ACCUM 52X0.5 G230L 2376 PATTERN=ALONG-SLIT,NUM-POS=2, 1 300 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV4 STIS/F ACCUM 52X0.5 G140L 1425 PATTERN=ALONG-SLIT,NUM-POS=2, 1 450 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 5] Visit: 02 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 25 AZV218 STIS/C ACQ F28X50L MIRROR 1 0.2 S ONBOARD ACQ FOR 30 CD P ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV218 STIS/F ACCUM 52X0.5 G140L 1425 PATTERN=ALONG-SLIT,NUM-POS=2, 1 450 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV218 STIS/N ACCUM 52X0.5 G230L 2376 PATTERN=ALONG-SLIT,NUM-POS=2, 1 300 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 6] Visit: 03 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 25 AZV132 STIS/C ACQ F28X50L MIRROR 1 0.2 S ONBOARD ACQ FOR 50 CD P ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV132 STIS/F ACCUM 52X0.5 G140L 1425 PATTERN=ALONG-SLIT,NUM-POS=2, 1 450 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV132 STIS/N ACCUM 52X0.5 G230L 2376 PATTERN=ALONG-SLIT,NUM-POS=2, 1 300 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 7] Visit: 04 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 25 AZV86 STIS/C ACQ F28X50L MIRROR 1 0.1 S ONBOARD ACQ FOR 70 CD P ------------------------------------------------------------------------------------------------------------------------------------ 70 AZV86 STIS/F ACCUM 52X0.5 G140L 1425 PATTERN=ALONG-SLIT,NUM-POS=5, 1 100 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 80 AZV86 STIS/N ACCUM 52X0.5 G230L 2376 PATTERN=ALONG-SLIT,NUM-POS=5, 1 100 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 8] Visit: 05 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 25 AZV23 STIS/C ACQ F28X50L MIRROR 1 0.1 S ONBOARD ACQ FOR 90 CD P ------------------------------------------------------------------------------------------------------------------------------------ 90 AZV23 STIS/F ACCUM 52X0.5 G140L 1425 PATTERN=ALONG-SLIT,NUM-POS=2, 1 450 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 100 AZV23 STIS/N ACCUM 52X0.5 G230L 2376 PATTERN=ALONG-SLIT,NUM-POS=2, 1 300 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 9] Visit: 06 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 25 AZV404 STIS/C ACQ F28X50L MIRROR 1 0.1 S ONBOARD ACQ FOR 110 CD P ------------------------------------------------------------------------------------------------------------------------------------ 110 AZV404 STIS/F ACCUM 52X0.5 G140L 1425 PATTERN=ALONG-SLIT,NUM-POS=5, 1 120 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 120 AZV404 STIS/N ACCUM 52X0.5 G230L 2376 PATTERN=ALONG-SLIT,NUM-POS=5, 1 100 S UV-MAM STEP-SIZE=1.0, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8198( 4) - 02/29/00 11:19 - [ 10] Summary Form for Proposal 8198 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.5 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PATTERN=ALONG-SLIT NUM-POS=2 STEP-SIZE=1.0 PATTERN-DIRECTION=PLUS NUM-POS=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 10 ONBOARD ACQ FOR 30 ONBOARD ACQ FOR 50 ONBOARD ACQ FOR 70 ONBOARD ACQ FOR 90 ONBOARD ACQ FOR 110 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G230L G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names AZV4 AZV218 AZV132 AZV86 AZV23 AZV404 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2376 1425 ------------------------------------------------------------------------------------------------------------------------------------